Probiotic Supplementation Regulated Swine Growth Performance, Fecal Odor Reduction and Carcass Characteristics by Modulating Intestinal Microbiome and Butanoate Metabolism

Using probiotics as a substitute for antibiotic growth promoters and reducing odor has received increasing attention in animal science. Despite the extensive investigation into the effects of probiotic administration on swine growth performance and odor reduction by short study durations, the analysis of carcass characteristics and potential mechanistic insights involving gut microbiota and downstream pathways is still few. In this study, the 48 LYD crossbred piglets treated with three probiotic strains, Lactobacillus kefiranofaciens M1, Bacillus subtilis S14, and B. amyloliquefaciens S20 were divided into four groups: a control (CON) group, M1 group, SA group, and SAM group. A pig-feeding experiment was conducted from the weaning period to the finishing phase, during which growth performance, fecal odor, intestinal microbiota, and carcass characteristics were analyzed. The results demonstrated that administration of the probiotics led to increased body weight and average daily weight gain, particularly notable during the weaning and finishing periods. Additionally, the SA and SAM groups significantly reduced skatole concentration in feces, thereby mitigating fecal odor. Furthermore, probiotic supplementation was associated with increased carcass weight, with the SAM group exhibiting significantly higher tenderloin weight than the CON group. Microbiota analysis revealed taxa exhibiting significant differences in abundance among groups, with corresponding LEfSe findings identifying them as crucial gastrointestinal bacterial biomarkers. Spearman correlation coefficient analysis further indicated higher levels of skatole, urease, and butanoate metabolism function in probiotic-treated groups compared to CON groups. Administering Bacillus subtilis S14 and B. amyloliquefaciens S20 (SA group) impacted growth performance, reduced fecal odor, and enhanced pig carcass quality. The identified probiotic strains hold promise as feed additives, offering a potential solution to challenges encountered by the swine industry.